The present invention relates to an ink mist type high speed printer.
The operational speed of an information processing system including a computer system has recently been improved, thus requiring the use of a high speed peripheral device including a printer. A conventional high speed printer is a line printer with a type drum or a type train. However, this line printer has many disadvantages, some of which are that the operational speed is not sufficient for the latest information processing system, and the process involves a high level of sound noise and/or limitation of the number of printing types. In order to overcome these disadvantages, some high speed printers with new operational principles have been developed. Among them, one of the most promising is an ink mist type printer, which operates at high speed, i.e. 8,000 lines per minute, with a low sound noise level. Further, it can type not only alphanumeric characters but also Chinese or Japanese characters.
The operational principle of an ink mist type printer is that an ion stream generated by corona discharge passes through apertures of an aperture board and ionizes an ink mist, and the movement of the electrically charged ink mist is accelerated by a negative electrode and is attached to paper according to the pattern of characters.
The main disadvantage of the prior ink mist type printer is that a positive electrode for generating said ion stream sometimes causes an undesirable discharge between the positive electrode and the aperture board. Said undesirable discharge damages a drive circuit connected to a selection electrode of the aperture board, and further, the aperture board is corroded by ozone gas generated by said undesirable discharge.